Question: $\Huge{21 - 1.026 = {?}}$
${2}$ ${1}$ ${0}$ ${0}$ ${0}$ ${0}$ ${1}$ ${0}$ ${2}$ ${6}$ ${-\vphantom{0}}$ ${.}$ ${.}$ ${.}$ $\text{Make sure the decimals are lined up.}$ ${2}$ ${1}$ ${0}$ ${0}$ ${0}$ ${0}$ ${1}$ ${0}$ ${2}$ ${6}$ ${-\vphantom{0}}$ ${.}$ ${.}$ ${.}$ ${10}$ ${0}$ ${10}$ ${9}$ ${10}$ ${9}$ ${{6}}$ ${4}$ ${{4}}$ ${{10} - {6} = {4}}$ ${2}$ ${1}$ ${0}$ ${0}$ ${0}$ ${0}$ ${1}$ ${0}$ ${2}$ ${6}$ ${-\vphantom{0}}$ ${.}$ ${.}$ ${.}$ ${10}$ ${0}$ ${9}$ ${4}$ ${9}$ ${{2}}$ ${7}$ ${{7}}$ ${{90} - {20} = {7}0}$ ${2}$ ${1}$ ${0}$ ${0}$ ${0}$ ${0}$ ${1}$ ${0}$ ${2}$ ${6}$ ${-\vphantom{0}}$ ${.}$ ${.}$ ${.}$ ${0}$ ${4}$ ${7}$ ${9}$ ${{0}}$ ${9}$ ${{9}}$ ${{900} - {0} = {9}00}$ ${2}$ ${1}$ ${0}$ ${0}$ ${0}$ ${0}$ ${1}$ ${0}$ ${2}$ ${6}$ ${-\vphantom{0}}$ ${.}$ ${.}$ ${.}$ ${4}$ ${7}$ ${9}$ ${10}$ ${1}$ ${{1}}$ ${9}$ ${{9}}$ ${{10000} - {1000} = {9}000}$ ${2}$ ${1}$ ${0}$ ${0}$ ${0}$ ${0}$ ${1}$ ${0}$ ${2}$ ${6}$ ${-\vphantom{0}}$ ${.}$ ${.}$ ${.}$ ${4}$ ${7}$ ${9}$ ${9}$ ${1}$ ${{0}}$ ${1}$ ${{1}}$ ${{10000} - {0} = {1}0000}$ ${2}$ ${1}$ ${0}$ ${0}$ ${0}$ ${0}$ ${1}$ ${0}$ ${2}$ ${6}$ ${-\vphantom{0}}$ ${.}$ ${.}$ ${.}$ ${4}$ ${7}$ ${9}$ ${9}$ ${1}$